Nice project so far. Looks like you are making progress. Maybe im confused on what you're doing with your steering box but $500 for the DD joints and a Shaft? you could use the two joints below and just a standard DD shaft and accomplish what you're going for i think and be money ahead
https://www.brotherstrucks.com/47-91...info/CSC72UJ1/
https://www.brotherstrucks.com/47-91...tinfo/CSC72UJ/
Might wanna give em a call on this one, i cant remember if its a DD shaft on both ends, pretty sure but ya. .
https://www.brotherstrucks.com/47-91...tinfo/CSC72SH/